Poser's jpg exporter is beyond crappy. It's really useless, it compresses everything to a degree where even a blind man would cringe at the sight.

Use something else. And then convert it to jpg in another program. SlowView is great, and free. (or Photoshop et. al. of course if you've got those... but if you do, you probably wouldn't even consider saving as jpg from Poser in the first place...)

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You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.